Power supply unit and manufacturing method of the same

ABSTRACT

A fuel cell unit includes a lower case and an upper case. A cell stack of multiple fuel cells is accommodated in the lower case. The upper case is coupled to the lower case. Substrates on which electronic components are implemented are mounted to an inner side of the upper case. A wall extending from a top plate of the upper case is provided between a side plate of the upper case and the substrates. When the upper case is turned, the wall prevents falling dust from adhering to the substrates.

INCORPORATION BY REFERENCE

The disclosure of Japanese Patent Application No. 2017-226544 filed onNov. 27, 2017 including the specification, drawings and abstract isincorporated herein by reference in its entirety.

BACKGROUND 1. Technical Field

The technique disclosed in the present specification relates to a powersupply unit including a fuel cell or a battery and electroniccomponents, and a manufacturing method of the same.

2. Description of Related Art

There has been known a power supply unit having a case or multiplecoupled cases in which a fuel cell or a battery and electroniccomponents are accommodated. In Japanese Patent Application PublicationNo. 2017-152286, International Publication No. WO 2012/150629, JapanesePatent Application Publication No. 2009-190438, and Japanese PatentApplication Publication No. 2007-207582, examples of power supply unitsincluding fuel cells as power supplies are disclosed. JP 2017-152286 Adiscloses a fuel cell unit including: a lower case in which fuel cellsare accommodated; and an upper case in which electronic components areaccommodated. The upper case is coupled onto the lower case. Some of theelectronic components are mounted onto a back side of a top plate of theupper case.

SUMMARY

When the power supply unit having the coupled cases as disclosed in JP2017-152286 A is assembled, the following procedure is taken. First, theupper case is held in a posture in which the top plate faces downwardand an opening faces upward. Then, the electronic components are mountedonto the back side of the top plate. Thereafter, the upper case isturned over 180 degrees. The upper case is then coupled to the lowercase in which the power supply is accommodated. Along with the turningof the upper case, dust and foreign substances present in the upper casemove. If the components mounted onto the back side of the top plate aresubstrates on which electronic components are implemented, dust andforeign substances might adhere to the electronic components that areexposed to the outside when the upper case is turned. To cope with this,provided is such a technique that, in a power supply unit includingsubstrates mounted onto a back side of a top plate of an upper case,suppresses adhesion of dust and foreign substances to the substrateswhile the power supply unit is manufactured.

A power supply unit disclosed in the present specification includes: alower case and an upper case. A fuel cell or a battery is accommodatedin the lower case. The upper case is coupled to the lower case.Substrates on which electronic components are implemented are mounted toan inner side of the upper case. A wall extending from a top plate ofthe upper case is provided between a side plate of the upper case andthe substrates. This power supply unit includes the wall to protect thesubstrates from dust and foreign substances when the upper case isturned. Accordingly, when the upper case is turned in the manufacturingprocess of the power supply unit, dust and foreign substances areunlikely to adhere to the substrates.

In order to manufacture the above-described power supply unit, anassembling step, a turnover step, and a coupling step may be provided.In the assembling step, while the upper case is held in a posture inwhich its inner side faces upward, the substrates are mounted to theinner side of the upper case. In the turnover step, getting through astate in which the wall is located over the substrates, the upper caseis turned over in the height direction. In the coupling step, the uppercase with the opening facing downward is coupled to the lower case. Whenthe upper case is turned over as described in the turnover step, dustand foreign substances present above the substrates fall down toward thesubstrates during the turnover. However, the dust and the foreignsubstances are blocked by the wall, to thereby prevent them fromadhering to the substrates.

In the power supply unit, the reactors may be disposed on the oppositeside of the substrates from the wall. In addition, a terminal base towhich conductors extending from the reactors are connected may bemounted to the top plate, between the substrates and the reactors. Thereactors may be mounted to the top plate, and cables extending from thereactors may be fixed to a side plate of the upper case. The wall may beintegrally formed with the upper case. Furthermore, the wall may beformed by a sheet member made of resin.

Details and further improvement of the technique disclosed in thepresent specification will be explained in the following “DETAILEDDESCRIPTION OF EMBODIMENTS”.

BRIEF DESCRIPTION OF THE DRAWINGS

Features, advantages, and technical and industrial significance ofexemplary embodiments of the disclosure will be described below withreference to the accompanying drawings, in which like numerals denotelike elements, and wherein:

FIG. 1 is a perspective view showing a layout of components in an uppercase of a fuel cell unit of an embodiment;

FIG. 2 is a sectional view taken along line II-II of FIG. 1;

FIG. 3 is a plan view of an upper case as viewed from its opening;

FIG. 4 is a sectional view of the fuel cell unit;

FIG. 5 is a view explaining a manufacturing method of the fuel cellunit;

FIG. 6 is a view explaining the manufacturing method of the fuel cellunit;

FIG. 7 is a view explaining the manufacturing method of the fuel cellunit;

FIG. 8 is a view explaining the manufacturing method of the fuel cellunit;

FIG. 9 is a perspective view showing an layout of components in an uppercase of a modification; and

FIG. 10 is a sectional view taken along line X-X of FIG. 9.

DETAILED DESCRIPTION OF EMBODIMENTS

A power supply unit of an embodiment will be described with reference tothe drawings. The power supply unit of the embodiment is a fuel cellunit 2 including fuel cells as a power supply. The fuel cell unit 2 ofthe embodiment is used as a power supply for a traction motor, and isinstalled in an automobile. A case of the fuel cell unit 2 is dividedinto an upper case 10 and a lower case 30. A stack of multiple fuelcells is accommodated in the lower case 30, and various electroniccomponents are accommodated in the upper case 10.

FIG. 1 shows a perspective view of the upper case 10. FIG. 2 shows asectional view taken along line II-II of FIG. 1. FIG. 3 shows a planview of the upper case 10 as viewed from the opening 109 side. FIG. 4shows a sectional view of the fuel cell unit 2. Note that FIG. 1 is aperspective view showing the upper case 10 set upside down. That is, aplate appearing like a bottom plate in FIG. 1 is a top plate 101 locateduppermost in the fuel cell unit 2. Each of coordinates in the drawingsindicates a global coordinate system that is a coordinate not fixed tothe upper case 10, and a +Z direction indicates “upward”. FIG. 2 is asectional view also showing the upper case 10 in the upside down state.In FIG. 3, for convenience of explanation, an illustration of a stackunit 12 (described later) is omitted, while a substrate 14 under thestack unit 12 is illustrated. Other electric components are accommodatedat frontward positions of the stack unit 12 (in the −X direction fromthe stack unit 12) in FIG. 1, and below the stack unit 12 (in the −Xdirection from the stack unit 12) not illustrated in FIG. 3. However, inthe present embodiment, for the purpose of easy understanding of thelayout of the stack unit 12 and substrates 13, 14, illustrations of theother electronic components are omitted.

The manufacturing method of the fuel cell unit 2 will be describedlater. The upper case 10 is held with its inner side facing upward, andvarious components are mounted to the upper case 10. Subsequently, asindicated by a bold arrow line A of FIG. 1, the upper case 10 is turnedover 180 degrees, and then the upper case 10 is coupled to a lower case(not illustrated). FIG. 4 shows a sectional view of the fuel cell unit 2in a state in which the upper case 10 is coupled to the lower case 30.As shown in FIG. 4, in the upper case 10, the top plate 101 is locatedon the top of the upper case 10, and the opening 109 faces the lowercase 30. As shown in FIG. 1, holes (jig holes 108) used for fixing jigsthat allow the upper case 10 to be turned over are provided in sidesurfaces of the upper case 10.

The layout of the components in the upper case 10 will be described.Electronic components accommodated in the upper case 10 configure astep-up converter circuit to step up the output voltage of the fuelcells. The step-up converter circuit is of a chopper type, and includesseveral switching elements and reactors 15 as main components thereof.The output of the fuel cells greatly varies. For this reason, the fuelcell unit 2 includes a multi-phase converter. Therefore, the fuel cellunit 2 includes multiple reactors 15 corresponding to respective phasesof the multi-phase converter.

The switching elements as main components of the multi-phase converterare distributed into multiple card-type power modules 122. The multiplepower modules 122 and multiple card-type coolers 121 are alternatelystacked one by one so as to configure the stack unit 12. In theperspective view of FIG. 1, reference numerals are added to only thepower modules 122 and the coolers 121 located most frontward in thisdrawing, and reference numerals for the other power modules and coolersare omitted. The adjacent coolers 121 are connected to each other withconnecting tubes. Although not illustrated in the drawings, the multiplecoolers 121 of the stack unit 12 are connected to an external radiatorof the fuel cell unit 2 through circulation passages. Coolant iscirculated between the multiple coolers 121 and the radiator so as tocool the power module 122. The stack unit 12 is fixed to the frame. Theframe is fixed to the upper case 10. Illustration of the frame isomitted in the drawing.

As aforementioned, the multiple reactors 15 are accommodated in theupper case 10. As shown in FIG. 2, a coolant passage 105 is formed in apart of the top plate 101 of the upper case 10. The multiple reactors 15are mounted on the back side of the top plate 101 so as to face thecoolant passage 105. Each of the reactors 15 is provided with atemperature sensor 151. A signal cable 152 of each temperature sensor151 is fixed, via a clamper 153, to a side plate 102 among multiple sideplates of the upper case 10, the side plate 102 being closer to thereactor 15. The signal cables 152 extending from the respectivetemperature sensors 151 of the reactors 15 are joined to a main cable154. In the plan view of FIG. 3, an illustration of the main cable 154is partially omitted. In addition, in FIG. 1 and FIG. 3, referencenumerals for some of the components pertaining to the reactors 15 areomitted.

A bus bar 161 is connected to a coil (not illustrated) of each reactor15. The other end of each bus bar 161 is fixed to a terminal base 16. InFIG. 1 and FIG. 3, no reference numerals are added to some of the busbars. The bus bars 161 connected to the respective reactors 15 areconnected, via the terminal base 16, to power terminals 122 a, 122 b ofthe power module 122 of the stack unit 12. In the drawings,illustrations of different bus bars that connect the terminals 122 a,122 b of the power module 122 to the bus bars 161 are omitted.

The substrates 13, 14 are disposed between the stack unit 12 and the topplate 101. The substrates 13, 14 are mounted onto the back side of thetop plate 101. Multiple signal terminals 124 extending from the powermodule 122 are connected to the substrate 14. The signal terminals 124are gate terminals electrically connected to gates of switching elementsaccommodated in the power module 122, and sensor terminals of thetemperature sensors that measure temperatures of the switching elements,etc. Various electronic components 131, 141 and others that realizedriving circuits for the switching elements accommodated in the powermodule 122 are implemented on the substrates 13, 14.

The various electronic components 131, 141 and others are implemented onthe substrates 13, 14. If dust and foreign substances adhere to thesubstrates 13, 14 on which the electronic components 131, 141 and othersare implemented, the dust and foreign substances might causemalfunctions to the electronic components 131, 141 and others. In themeantime, as aforementioned, in the manufacturing step of the fuel cellunit 2, the components (including the substrates 13, 14) are mountedwhile the upper case 10 is held with the opening 109 facing upward.Then, the upper case 10 is turned over 180 degrees. When the upper case10 is turned over, dust and foreign substances present in the upper case10 might move, and these dust and foreign substances might adhere to thesubstrates 13, 14. For this reason, in the fuel cell unit 2 of theembodiment, there is provided a wall 9 to prevent dust and foreignsubstances from adhering to the substrates 13, 14 when the upper case 10is turned over. Hereinafter, for simple explanation, “dust and foreignsubstances” are referred to as “dust”. Typical dust is dust that adheresto the inner side of the upper case 10 in the manufacturing process.

The wall 9 is provided on the back side of the top plate 101 of theupper case 10. The wall 9 extends along the substrates 13, 14. Althoughthe manufacturing method of the upper case 10 will be described later,the upper case 10 set upside down in the height direction is turned over180 degrees around the rotation axis (one dot chain line CL in FIG. 1)extending in parallel to the extending direction of the wall 9. The boldarrow line A of FIG. 1 indicates the turning direction. Getting througha state in which the wall 9 is located over the substrates 13, 14, theupper case 10 is turned over.

As shown in FIG. 2, a height of the wall 9 extending from the backsurface of the top plate is higher than heights of the substrates 13, 14extending from the back surface of the top plate. As shown in FIG. 3,the length of the wall 9 is longer than lengths of the substrates 13,14. The wall 9 has a dimension large enough to hide the substrates 13,14 therebehind, as viewed from the opposite side of the wall 9 from thesubstrates 13, 14.

The wall 9 is a part of the upper case 10. The upper case 10 is formedby injection-molding aluminum. The wall 9 is formed throughinjection-molding at the same time of manufacturing the upper case 10.

The wall 9 extends in parallel to the rotation axis CL around which theupper case 10 is turned over. When the upper case 10 set upside down isturned over 180 degrees, the upper case 10 is turned over such that thewall 9 moves over the substrates 13, 14 around the rotation axis CLparallel to the extending direction (X-axis direction in the drawings)of the wall 9. This procedure allows the dust present above thesubstrates 13, 14 to fall down during the turnover. In spite of thisfalling, the dust is blocked by the wall 9 from adhering to thesubstrates 13, 14. The dust present below the substrates 13, 14 moves ina direction away from the substrates 13, 14 during the turning(turnover) of the upper case 10. Accordingly, the dust is prevented fromadhering to the substrates 13, 14 as well. The wall 9 prevents dustpresent above the substrates 13, 14 from falling down onto thesubstrates 13, 14 when the upper case 10 set upside down is turned over.

With reference to FIG. 4, the layout of the components inside the lowercase 30, and how the lower case 30 is coupled to the upper case 10 willbe described. A cell stack 40 of multiple fuel cells are accommodated inthe lower case 30. In FIG. 4, the section of the cell stack 40 isuniformly hatched, and thus an illustration of the internal structure ofthe cell stack 40 is omitted. The upper case 10 is coupled onto the topof the lower case 30 with the opening 109 facing toward the lower case30 side. A flange 104 is formed around the opening 109 of the upper case10. The upper case 10 is disposed on the lower case 30 such that theflange 104 meets a flange 301 of an opening of the lower case 30. Theboth flanges of the upper case 10 and the lower case 30 are coupled toeach other with multiple bolts 302.

A cell monitor unit 41 is attached onto the top of the cell stack 40 ofthe fuel cells. The cell monitor unit 41 is a device to monitor voltageof the fuel cells. The upper part of the cell monitor unit 41 extends tothe inner side of the upper case 10, so that a part of this upper partenters a space between the side plate 103 and the wall 9 of the uppercase 10. In FIG. 4, the cell stack 40 and the cell monitor unit 41 areschematically illustrated, and thus illustrations of signal wiresextending from the respective components are omitted.

The manufacturing method of the fuel cell unit 2 will be described withreference to FIG. 5 to FIG. 8.

Assembling Step

As shown in FIG. 5, the upper case 10 is held with the top plate 101facing downward and the inner side of the upper case 10 facing upward;and in this state, the substrates 13, 14 and the other components areassembled to the upper case 10. FIG. 5 shows that the reactors 15 arealready mounted. The signal cables 152 extending from the temperaturesensors 151 are fixed to the side plate 102 with the clampers 153. Thebus bars 161 extending from the respective reactors 15 are fixed to theterminal base 16. The bus bars 161 are connected, via different busbars, to the power terminals 122 a, 122 b of the power module 122 at theterminal base 16. Illustrations of the different bus bars are omitted inthe drawings.

The substrate 13 is fixed onto the back side of the top plate 101 viafirst spacers 132, and the substrate 14 is fixed onto the substrate 13via second spacers 133. The multiple electronic components 131 arepreviously implemented on the substrate 13. The multiple electroniccomponents 141 are previously implemented on the substrate 14. Thesubstrates 13, 14 are located between the wall 9 and the terminal base16 and fixed onto the back side of the top plate 101. The terminal base16 is fixed onto the back side of the top plate 101. There is noclearance between the terminal base 16 and the top plate 101.

Even if the dust 90 adheres to a part of the upper case 10 between theside plate 103 and the wall 9, the dust 90 is prevented by the wall 9from adhering to the substrates 13, 14 during the turnover of the uppercase 10. This will be described as follows.

Turnover Step

FIG. 6 is a sectional view of the upper case 10 to which the componentsare assembled. FIG. 6 shows that the upper case 10 is held in a state ofbeing upside down in the height direction. In the turnover step, theupper case 10 set upside down in the height direction is turned over 180degrees. As shown in FIG. 1, the rotation axis CL extends in thedirection parallel to the X-axis. In other words, the rotation axis CLextends in the direction parallel to the extending direction of the wall9. A bold arrow line B of FIG. 6 indicates the direction of theturnover.

FIG. 7 is a drawing showing the upper case 10 on the way of theturnover. FIG. 7 shows a state in which the upper case 10 is turned over90 degrees from the state shown in FIG. 6. The upper case 10 is turnedover such that the wall 9 moves over the substrates 13, 14. When theupper case 10 is turned over 90 degrees, the wall 9 is located rightabove the substrates 13, 14. When the dust 90 perpendicularly falls down(in the −Z direction), the dust 90 is blocked by the wall 9 so as not toreach the substrates 13, 14. That is, the wall 9 can prevent the dustfrom adhering to the substrates 13, 14 during the turning.

During the turning, dust present below the substrates 13, 14 moves inthe direction away from the substrates 13, 14 due to the turning, andthus the dust is prevented from adhering to the substrates 13, 14. Evenwhen the dust present below the substrates 13, 14 is whirled up, theterminal base 16 extending along the substrates 13, 14 functions as awall to prevent the dust from adhering to the substrates 13, 14.

The upper case 10 is further turned over 90 degrees from the state shownin FIG. 7. A bold arrow line C of FIG. 7 indicates the direction of theturning. That is, in the turnover step, getting through the state (stateshown in FIG. 7) in which the wall 9 is located over the substrates 13,14, the upper case 10 is turned over in the height direction.

Coupling Step

FIG. 8 shows a sectional view of the upper case 10 turned over and thelower case 30. When the upper case 10 is turned over, the opening 109faces downward. The upper case 10 with the opening 109 facing downwardis disposed on the lower case 30. A flange surface of the flange 104 ofthe upper case 10 and a flange surface of the flange 301 of the lowercase 30 are brought to meet each other, and the both surfaces are thenfixed to each other with bolts 302. In this manner, the fuel cell unit 2is completed.

An upper case 10 a of a modification will be described with reference toFIG. 9 and FIG. 10. FIG. 9 is a perspective view showing a layout ofcomponents in the upper case 10 a of the modification. FIG. 10 is asectional view taken along line X-X of FIG. 9. FIG. 9 and FIG. 10 eachshow the upper case 10 a set upside down.

In the upper case 10 a of the modification, a wall 19 is formed by asheet-like member made of resin. The wall 19 includes a top-plate facingportion 19 b, a dust protecting portion 19 a, and a back surface portion19 c. The top-plate facing portion 19 b faces a back surface of the topplate 101 a. The dust protecting portion 19 a is bent from the edge ofthe top-plate facing portion 19 b at a substantially right angle. Theback surface portion 19 c intersects the top-plate facing portion 19 band the dust protecting portion 19 a at a substantially right angle,respectively. The dust protecting portion 19 a is located between thesubstrates 13, 14 and the side plate 103, and extends from the top plate101 a in generally parallel to the side plate 103. The top-plate facingportion 19 b is located between the top plate 101 a and the substrates13, 14. During the assembly of the fuel cell unit 2, the upper case 10 ais held with the top plate 101 a facing downward and the opening 109facing upward, and in this state, the substrates 13, 14 and othercomponents are assembled onto the back side of the top plate 101 a. Thewall 19 is fixed onto the back side of the top plate 101 a at the sametime. Subsequently, getting through the state in which the wall 19 islocated over the substrates 13, 14, the upper case 10 a is turned overin the height direction. A bold arrow line D of FIG. 10 indicates theturning direction. During the turnover, the dust 90 present between thewall 19 and the side plate 103 is blocked by the wall 19 when fallingdown, thus to be prevented from adhering to the substrates 13, 14. Theupper case 10 a having the wall 19 exerts the same operational effect asthat of the upper case 10.

The technical features explained in the embodiment will be summarized asbelow. The fuel cell unit 2 includes the lower case 30 and the uppercase 10 (10 a). The cell stack 40 of the multiple fuel cells isaccommodated in the lower case 30. The upper case 10 (10 a) is coupledto the top part of the lower case 30 so as to be coupled to the lowercase 30 (such that the opening 109 is coupled to the inner side of thelower case 30). The substrates 13, 14 are mounted onto the back side ofthe top plate 101 of the upper case 10 (10 a). The electronic components131, 141 are implemented on the substrates 13, 14, and adhesion of dustmight cause malfunction to these electronic components. The wall 9 (wall19) is provided on the back side of the top plate 101 of the upper case10 so as to extend along the substrates 13, 14. The wall may beintegrally formed with the upper case 10, as similar to the wall 9. Thewall may be formed by a sheet-like member made of resin, as similar tothe wall 19. The components such as the substrates 13, 14 are mounted tothe upper case 10 (10 a) with the inner side of the upper case 10 (10 a)facing upward. The upper case 10 (10 a) is turned over 180 degrees so asto be coupled to the lower case 30. The wall 9 (wall 19) extends inparallel to the axis (axis CL of FIG. 1) around which the upper case 10(10 a) is turned over. Getting through the state in which the wall 9(wall 19) is located over the substrates 13, 14, the upper case 10 (10a) is turned over. In the turnover of the upper case 10 (10 a), dustpresent above the substrates 13, 14 is blocked by the wall 9 (wall 19)when falling down, thus to be prevented from adhering to the substrates13, 14.

Other technical features of the technique described in the embodimentwill be described. The reactors 15 are disposed in the upper case 10 (10a) and on the opposite side of the substrates 13, 14 from the wall 9(wall 19). When the upper case 10 (10 a) is turned over, the reactors 15move below the substrates 13, 14. When foreign substances adhering tothe reactors 15 fall down, they move in a direction away from thesubstrates 13, 14. This means that the foreign substances adhering tothe reactors 15 do not adhere to the substrates 13, 14 when the uppercase 10 (10 a) is turned over.

The terminal base 16 to which the bus bars 161 (conductors) extendingfrom the respective reactors 15 are connected is mounted to the topplate 101, at a position between the substrates 13, 14 and the reactors15. The terminal base 16 extends along the substrates 13, 14. Theterminal base 16 extends in parallel to the rotation axis around whichthe upper case 10 (10 a) is turned over. No clearance is providedbetween the terminal base 16 and the top plate 101. The terminal base 16located on the opposite side from the wall 9 (wall 19) serves as a wallto protect the substrates 13, 14. During the turning of the upper case10 (10 a), even when dust present below the substrates 13, 14 is whirledup, the terminal base 16 blocks the dust. Accordingly, the dust isprevented from adhering to the substrates 13, 14.

The electric cables (signal cables 152) extending from the reactors 15are fixed to the side plate 102 of the upper case 10 (10 a). Thereactors 15 have a large calorific value. The electric cables (signalcables 152) are fixed to the side plate 102 on the lateral side of thereactors 15, to thereby suppress increase in temperature of the electriccables (signal cables 152) resulting from heating of the reactors 15.

The wall 19 formed by the sheet-like member made of resin has a lighterweight than that of the wall 9 integrally formed with the upper case 10.Accordingly, it is possible to promote weight reduction of the fuel cellunit by employing the sheet-like member made of resin.

In the fuel cell unit 2, the cell stack 40 is accommodated in the lowercase 30, and the various electronic components are accommodated in theupper case 10. The fuel cell unit 2 includes no intermediate plate topartition the upper case 10 from the lower case 30. Because of having nointermediate plate, the height of the fuel cell unit 2 can be lowered.

Remarks regarding the technique described in the embodiment will bedescribed. The components accommodated in the upper case 10 (10 a) ofthe embodiment are electronic components mainly configuring the step-upconverter circuit. The electronic components configuring the drivingcircuit of the step-up converter are implemented on the substrates 13,14. However, any type of electronic components may be implemented on thesubstrates 13, 14.

The power supply unit of the embodiment is a fuel cell unit includingfuel cells. The technique disclosed in the present specification may beapplied to a power supply system in which a battery is accommodated,instead of the fuel cells.

The specific examples of the present disclosure have been describedabove in detail, but these are merely exemplifications, and should notlimit the scope of the claims. The art described in the claims includesthose obtained by modifying and altering the specific examplesexemplified above in various manners. The technical elements describedin the present specification or the drawings are technically usefulalone or in various combinations, and should not be limited to thecombinations described in the claims at the time of the filing of theapplication. Besides, the art exemplified in the present specificationor the drawings can achieve a plurality of objects at the same time, andis technically useful by achieving one of the objects itself.

What is claimed is:
 1. A power supply unit comprising: a lower case inwhich a fuel cell or a battery is accommodated; and an upper casecontaining substrates that are mounted to an inner side of the uppercase, electronic components being implemented on the substrates, theupper case being coupled to the lower case, wherein a wall extendingfrom a top plate of the upper case is provided between a side plate ofthe upper case and the substrates.
 2. The power supply unit according toclaim 1, wherein reactors are disposed on an opposite side of thesubstrates from the wall.
 3. The power supply unit according to claim 2,wherein a terminal base is mounted to the top plate at a positionbetween the substrates and the reactors, and conductors extending fromthe reactors are connected to the terminal base.
 4. The power supplyunit according to claim 2, wherein the reactors are mounted to the topplate, and cables extending from the reactors are fixed to a side plateof the upper case.
 5. The power supply unit according to claim 1,wherein the wall is integrally formed with the upper case.
 6. The powersupply unit according to claim 1, wherein the wall is formed by a sheetmember made of resin.
 7. A manufacturing method of a power supply unit,the power supply unit including: a lower case in which a fuel cell or abattery is accommodated; an upper case containing substrates that aremounted to an inner side of the upper case, electronic components beingimplemented on the substrates, the upper case being coupled to the lowercase; and a wall extending from a top plate of the upper case, the wallbeing provided between a side plate of the upper case and thesubstrates, the manufacturing method comprising: holding the upper casewith the inner side of the upper case facing upward, and fixing thesubstrates to the upper case; turning over the upper case in a heightdirection after the upper case gets through a state in which the wall islocated over the substrates; and coupling the upper case to the lowercase.
 8. The manufacturing method of the power supply unit according toclaim 7, wherein reactors are disposed on an opposite side of thesubstrates from the wall.
 9. The manufacturing method of the powersupply unit according to claim 8, wherein a terminal base is mounted tothe top plate at a position between the substrates and the reactors, andconductors extending from the reactors are connected to the terminalbase.
 10. The manufacturing method of the power supply unit according toclaim 8, wherein the reactors are mounted to the top plate, and cablesextending from the reactors are fixed to a side plate of the upper case.11. The manufacturing method of the power supply unit according to claim7, wherein the wall is integrally formed with the upper case.
 12. Themanufacturing method of the power supply unit according to claim 7,wherein the wall is formed by a sheet member made of resin.